1640334402 has 80 divisors (see below), whose sum is σ = 4272016320. Its totient is φ = 460704672.

The previous prime is 1640334389. The next prime is 1640334407. The reversal of 1640334402 is 2044330461.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (1640334407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 54648 + ... + 79164.

It is an arithmetic number, because the mean of its divisors is an integer number (53400204).

Almost surely, 2^1640334402 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1640334402, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2136008160).

1640334402 is an abundant number, since it is smaller than the sum of its proper divisors (2631681918).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1640334402 is a wasteful number, since it uses less digits than its factorization.

1640334402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24597 (or 24588 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 27.

The square root of 1640334402 is about 40501.0419865959. The cubic root of 1640334402 is about 1179.3538552880.

Adding to 1640334402 its reverse (2044330461), we get a palindrome (3684664863).

It can be divided in two parts, 16403 and 34402, that added together give a palindrome (50805).

The spelling of 1640334402 in words is "one billion, six hundred forty million, three hundred thirty-four thousand, four hundred two".